1. Field of the Invention
The present invention generally relates to a portable terminal, and in particular, to a speaker device for a portable terminal, in which a better quality sound is produced by improving the sound pressure level, clearness, distortion and reinforcing a mid-bass of sound output.
2. Description of the Related Art
Generally, a “portable terminal” refers to an electronic apparatus, which provides electrical communication between users and service providers. Various applications such as voice communication, short message service, mobile banking service, TV watching, on-line game services, and on-demand video service are provided to via portable terminals.
Conventional portable terminals may be classified in various types according to their appearance. Portable communication terminals are classified as bar-type terminals, flip-type terminals, or folder-type terminals according to their appearance. In the bar-type terminal, input/output devices such as a communication circuit, a transmitting unit, and a receiving unit are mounted in a single housing. In a flip-type terminal, a flip cover is mounted on a bar-type terminal. In a folder-type terminal, a pair of housings are opened and closed through rotation and input/output devices are properly arranged over the pair of housings. Recently, a sliding-type terminal has been developed to improve portability user convenience, and satisfy various other user preferences.
As mobile communication services using portable terminals have been diversified, they not only provide voice communication and short message transmission but also transmission of games, music files, moving picture files, on-line games, multimedia services, and Digital Multimedia Broadcasting (DMB).
The display device of a portable terminal has already been equipped with a high-quality color screen using a Thin Film Transistor (TFT) device instead of a monochrome Liquid Crystal Display (LCD) device before commercialization of multimedia services and DMB. Using this display device, a portable terminal can provide sufficient performance to allow users to use multimedia services or watch DMB.
In order to provide a speaker device suitable for multimedia services and DMB services, separate speaker units are added to a single speaker unit that outputs a reception sound and a ring tone. Thus, the portable terminal can produce a stereo sound using the added speaker units.
However, the added speaker units cannot reach their full performance potential due to a limited space of the portable terminal. In other words, the sound pressure level, distortion, and clearness of the sound output are degraded. The sound in a bass region of the speaker units is inferior due to the limited space. As a result, users cannot enjoy a “live” sound when using multimedia services and DMB services.